The present invention concerns a watch of the type comprising a case provided with a back cover that is resistant to ambient pressure, a pressure sensor mounted in an orifice of the back cover with an intermediate ring, and a printed circuit element connected to terminals of the pressure sensor, said sensor comprising a rigid substrate fitted with said terminals, a tubular casing secured to the substrate in a water-resistant manner and arranged to fit into the intermediate ring, and a pressure sensitive element, which is mounted on the substrate and located inside the tubular casing.
In some watches having a pressure sensor mounted on the water-resistant back cover of the watchcase, vertical helical springs are provided for electrically connecting the terminals of the sensor to the main printed circuit of the watch. EP Patent No. 667 798 shows various possible arrangements of the sensor in the back cover of the watchcase, but in every case, the connecting springs are held in place by means of an insulating support plate which extends between the main printed circuit and the back cover. However, if one wishes to associate the sensor with a printed circuit element that directly processes these output signals, in particular to calibrate pressure measurements by calibrating parameters that are individually determined for each sensor, the construction is more complicated and problems arise in the precise mutual positioning of the electric contacts.
A watch with a pressure sensor of the type indicated hereinbefore appears in the drawings of JP Patent Application No. 2000-292559 A. The pressure sensor is driven into a pot-shaped intermediate element, whose peripheral cylindrical wall is itself driven into the orifice of the back cover of the case from the external side. It seems that this assembly enables rubber sealing gaskets to be omitted. However, the proper orientation of the assembly, in particular of the intermediate element, relative to the back cover is only guaranteed with the aid of visual markers. In fact, there is no need for a high level of positioning precision in this case, since the electrical connection between the sensor and the rest of the electronic circuits of the watch is achieved by means of a flexible printed circuit, welded to the terminals of the sensor. But if this flexible element has to connect the sensor to an additional printed circuit board to process the sensor signals, multiple, successive, sometimes difficult operations are required to mount these components respectively on the back cover and in the case.